Closure for pressure vessels

ABSTRACT

A closure for pressure vessels including a resilient seal ring having an outer lip and an inwardly turned flange angularly disposed to the outer lip whereby pressure within the vessel is exerted through an opening in the seal ring to urge the seal ring into positive sealing relation with the vessel around an opening in the vessel. The closure member has a seal ring receptacle having a plurality of anchor members secured thereto, said anchor members having surfaces engageable with slip rings to urge the slip rings into gripping engagement with a portion of the vessel.

PAIENTEDMAR 1 ma 3,647.V 10e SHEET 1 UF 2 /Vl/E/VTOR Norman H. Kemp 'By7M'w ,gawd/jm PATENTEDMAR 7 |972 y I3, 647. 108

snm a or 2 il 75g g /NVE/vof? 75 )C1-2.9.0121' Norman H. Kemp BY '-.ffiqJZ LA IQ!! CK w:

2 Arron/v ys CLOSUIRE FOR PRESSURE VESSlElLS BACKGROUND OF INVENTIONThis is a continuation-in-part of my copending Patent application Ser.No. 729,966, filed May l7, 1968, now U,S. Pat. No. 3,498,493, entitledClosure for Pressure Vessels, which is a continuation-in-part of Patentapplication Ser. No. 494,061, filed Oct. 8, |965, entitled Closure Seal,now U.S. Pat. No. 3,387,738.

The apparatus disclosed in the aforementioned applications offerssignificant improvements over sealing apparatus heretofore developed.The apparatus disclosed therein generally relates to a seal ring made ofresilient material having an outer lip and inwardly extending flangeangularly disposed with reference to the outer lip such that the sealring, which is slidably disposed in a receptacle having an annularskirt, may be positioned about an opening. Fluid pressure exertedthrough the opening urges the flange of the seal ring downwardly to sealabout the opening, while urging the annular lip outwardly to sealagainst the skirt of the receptacle.

Pressure vessels, such as tanks and pipe lines for storing andtransporting liquids and gases under pressure must meet certainstandards, as specified by regulatory authorities and users as tointernal pressure as to which they can be subject without rupturing orleaking, inasmuch as many of the liquids and gases stored andtransported therein are of volatile, noxious, flamable, and explosivecharacter. Such internal pressure tests, often made in pressure rangesto double the desired working pressure of the vessel, must be carriedout by the manufacturer as a safety precaution, to comply with the rulesof regulatory authorities and to meet the requirements of carriers andusers.

Prior to development of the invention described in the aforementionedpatents, difficulty had been encountered in carrying out such testingoperations due to the difficulty of properly sealing the opening oropenings in the tank, pipe, or other container during such testingoperations and in carrying out inspection tests to see that theprescribed standards were maintained after installation.

The apparatus disclosed in the aforementioned patents is very effectivefor sealing openings in pressure vessels, such as tanks and pipes.However, under certain operating conditions difficulty has beenexperienced in securing the seal ring receptacle or cover relative tothe pressure vessel, particularly in sealing vessels having straightcylindrical openings without flanged ends, such as smooth pipe.

Difficulty has been experienced in translating the force exerted bypressure in the pipe against the receptacle, tending to move thereceptacle longitudinally away from the pipe into a force exertedtransversely of the pipe to frictionally engage the surface of the pipeto secure the receptacle relative to the pipe. Certain grippingapparatus which effectively translates the longitudinally directed forceto a transversely directed force have resulted in bending or crushingthe end ofthe pipe, particularly in testing of relatively thin gaugetubular members.

The problems encountered in carrying out periodic inspection of pressurevessels are so similar to those encountered in testing that thedescription will be directed primarily to testing operations. However,it should be noted that the use of the embodiments of the closure andseal hereinafter described is not restricted to testing operations`SUMMARY OF INVENTION I have developed and improved closure for pressurevessels comprising the combination of a seal ring receptacle having aseal ring assembly slidably disposed therein which employs anchormembers having inclined surfaces on the lower ends thereof to translatelongitudinal forces into transversely directed forces to urge vsliprings into frictional engagement with sides of a conduit or standpipe.

The seal ring assembly comprises an annular stiffener or retainer ringhaving an annular shoulder on the outer periphery thereof, allowing theretainer ring to wobble or tilt relative to the receptacle in which itis slidably disposed. A resilient piston, or seal ring, is secured tothe retainer ring, said seal ring having an annular lip adapted to beurged into sealing relation with the inside walls of the skirt of thereceptacle in which the retainer ring and piston are slidably disposed.The retainer ring also has resilient seal means secured thereto, inspaced apart relation from the seal ring, said seal means being adaptedto be urged into sealing relation with the surface of the pressurevessel about the openings to be sealed.

A plurality of anchor members, having downwardly converging surfaces onlower portions thereof, are disposed in sliding relation with slip ringsegments having complementary inclined surfaces such that forces exertedthrough the anchor members longitudinally of a portion of the vessel aretranslated into transverse forces urging the slip ring segments intofrictional engagement with the outer walls of the vessel. The surfacesof the slip ring which are in engagement with the outer walls of theconduit have a high coefcent of static friction.

Suitable supporting apparatus is positioned inside the vessel to preventbending or deformation of the wall of the vessel as a result of theforces exerted on the outer surface thereof by the slip rings.

It is therefore a primary object of the present invention to provide animproved closure for pressure vessels wherein a seal is applied over andabout an opening in a pressure vessel, or other container, wherein theseal is actuated and uniformly applied by injecting pressure into thepressure vessel, container or conduit to positively close the opening,and wherein the greater the injected the pressure, the tighter the sealis applied.

Another object of the invention is to provide an improved closure forpressure vessels which provides means for sealing about an opening in apressure vessel, conduit or container, which may be easily and quicklyapplied over and about the opening, and which may be easily and quicklyremoved therefrom.

Another object of the invention is to provide an improved closure forpressure vessels which provides means for sealing over and about anopening in a pressure vessel or container to be tested which isadaptable and conformable to different types of openings, i.e., openingsthrough an extension or standpipe secured about the opening of a tank oropenings through the wall of a pressure vessel.

Still another object of the invention is to provide an improved closurefor pressure vessels in which the seal has a lower surface conformableto the surface about the opening and arranged to close bolt holesprovided through the wall of the tank about the opening or through aflange provided about the opening.

Still another object of the invention is to provide an improved closurefor pressure vessels adapted to grippingly engage the walls of pressurevessel to detachably secure the clo` sure relative to the vesselA Astill further object of the invention is to provide an improved closurefor pressure vessels which provides means to resist forces tending tocrush the vessel exerted by gripper means employed to connect theclosure member to the vessel.

A still further object of the invention is to provide a method ofsealing an opening in a tubular member comprising the steps ofreinforcing the walls of the tubular member, and grippingly securing aclosure member relative to the walls of the tubular member.

Other and further objects of the invention will become apparent uponreading the detailed specification hereinafter following and byreferring to the drawings annexed hereto.

DESCRIPTION OF THE DRAWlNGS Drawings of two preferred embodiments of theinvention are annexed hereto so that the invention may be better andmore fully understood, in which:

FIG. l is a top plan view of the closure apparatus;

FIG. ll is a cross-sectional view taken substantially along line ll-IIof FIG. I;

FlG. lll is a cross-sectional view line lll-[ll of FlG. lli;

FIG. lV is a cross-sectional view taken substantially along line lV-lVof FlG. ll;

FlG. V is a fragmentary cross-sectional view similar to PEG. Ilillustrating a modified form ofthe invention; and

FlG. Vl is a fragmentary elevational View of the apparatus employed in apressure testing operation.

Numeral references are employed to designate like parts throughout thevarious figures of the drawings.

taken substantially along DESCRlPTlON F A PREFERRED EMBODHMENT Referringto FIGS. l and ll of the drawing, the numeral i designates an inletconnection of a pressure vessel, pipe, conduit, tubular member, or othercontainer, having a passage 2 formed therein.

Such inlet connection is normally provided on pressure vessels used forstoring and dispensing liquefied petroleum gas, such as butane orpropane, and sometimes includes an annular flange (not shown) about theupper end thereof through which are provided spaced stud-receiving holesfor at tachment to a corresponding flange on a control head (not shown)mounted above same. Such control head normally provides a mounting fordispensing outlet, control valves, a pressure gauge, safety valve andother control devices nor mally required for connecting with suchequipment. Other connections besides a control head could be attached tothe inlet connection ll such as a conduit having a correspondingconnector thereon.

lt will be further understood that such type of inlet connection ismerely for illustration purposes and that the invention described andclaimed herein can be employed with different types and shapes of tankoutlets.

The closure apparatus, generally designated by the numeral 4l, ispositioned to engage and seal against the surface 6 of inlet connectionll around passage 2 which extends therethrough.

A dome-shaped cover il forms a receptacle having a threaded passage 9 inthe upper side thereof which is normally closed by a threaded plug i9.The threaded passage 9 provides an opening for bleeding or flushing airout of the tank or conduit before it is closed for testing. After thepressure vessel is thus flushed out the plug lli) may be threaded in thepassage 9 to provide a lealrproof closure during the testing operation.A suitable source of pressurized tluid may be connected through passage9 with the passage 2 if it is deemed expedient to do so.

The domelike cover i5 includes an annular downwardly ex tending skirtportion tia which has formed on its inner side an annular recess 2li forreceiving the seal ring assembly liti. Preferably the inner surface Ziaof the recess 2t is machined and finished to provide a smooth surfacefor receiving the seal hereinafter described.

Furthermore, it will be noted that the width of recess 2i is greaterthan the width of flange ll of seal aembly lo and greater in width thanthe shoulder on the outer periphery of stiffener or retainer ring i2.hereinafter more specifically described, so that the seal assembly litican move up and down to act as a piston in response to variations ofpressure within the dome Seal ring assembly )i6 comprises a stiffenerring l2, a resilient piston or seal ring M carried by the stiffener ringl2, and resilient seal means, such as gasket 2t carried by stiffenerring i2.

Stiffener ring l2 is preferably of rigid construction and has a recess22 formed in a lower portion thereof arranged to form a shoulder 2daround the periphery of stiffener ring E2.

Stiffener ring .l2 has a passage 2n formed in a central portion thereof,said passage forming a fluid connection between the passage 2 in inletconnection l and the inside of dome shaped cover 8 above piston assemblyi6.

Suitable connection means, such as transversely extending member 22?,having apertures Sib formed therein, is secured to seal ring assembly i6to which suitable means, such as stem 4u, to urge the seal ring assemblytoward the surface n on inlet connection ll may be connected ashereinafter more fully enplained.

The resilient piston or seal ring M is preferably made of resilientmaterial, such as neopreme or rubber compound, and includes an upwardlyextending annular lip i7 and flange itil being preferably, but notnecessarily, disposed in right angular relationship with reference tothe outer surface ll'a. The flange i8 is secured to stiffener ring l2 toprovide reinforcement to prevent undue extrusion of resilient materialinto passage 2 of inlet connection l and through any openings which maybe formed in or around the surface 6 against which seal assembly lo isurged. The seal ring lid might also be made of flexible, relativelypliable metal or other material which would provide a seal, such asaluminum, asbestos composition, Teflon, and the like.

To facilitate accomplishing a seal between the surface ti on inletconnection i and seal ring assembly i6, resilient seal means, such asgasket 20 is secured to stiffener ring l2. The degree of resiliency andthickness ofthe gasket 20 is, to some extent, dependent upon the sizeand shape of surface 6 of inlet connection ll.

ln the embodiment of the invention illustrated in FlG. li of thedrawing, the resilient piston lid is secured to stiffener ring l2 bythreaded bolts 3l which extend through apertures in backup member 32 andthrough apertures in flange i8 of seal ring ll/i to threadedly engagethreaded holes in stitener ring 112.

A conventional bonnet 3d extends through and is rigidly connected to, acentral portion of dome l5. Bonnet M has a threaded bore Siriathreadedly engaging threads 3S on the rising stem 40. Stem 4t) has ahandwheel 42 at the upper end thereof whereby rotation ofthe handwheeld2 rotates stem lltll thereby moving said stem axially relative to dome8.

Suitable packing material M is disposed about stem @il to preventleakage therearound.

Stem d@ has a reduced portion 46 at the lower end thereof for securingtransversely extending member 2&3 thereto by washers 413 and positionedon opposite sides of the central opening 12 in the transverselyextending member 2S and is secured thereto by a nut 5d which threadedlyengages the outer end of stern dil, lt will be noted that a space itinis provided between washers d8 and Sti and transversely extending member28, allowing seal ring assembly liti to move and float vertically towardand away from surface n on inlet connection ll. When pressure is appliedwithin passage 2 of inlet connecn tion ll, the seal ring assembly i6acts like a piston and moves toward surface 6 to form a positive sealtherewith.

Stern d@ facilitates positioning seal ring assembly llo and prevents itfrom falling out while cover il is being placed over passage 2, whilethe cap l is being transported, or while it is in storage.

Stiffener ring i2, having a tapered or relieved recess 22 forming ashoulder 2.4 adjacent the upper edge thereof, a.- lows stiffener ring l2and seal ring llll to float freely to conform to the configuration ofthe surface u of inlet connection i, thereby preventing sticking orwedging in the even seal ring assembly .lo is tilted out of a plzuieperpendicular to the axis of the passage 2.

Recess 22 also compensates for slight deformation of retainer ring i2when high pressure is applied thereto.

The outer surface la oflip i7 is preferably flat and closely conforms tothe inner surface 2in of the recess 2i provided on the inner side ofskirt 8a of cover il.

Suitable means for securing the dome-shaped cover to inlet connection iof a pressure vessel comprises means, such as anchor members 6@ andslipring segments 62, for translating force exerted against the cover d,tending to move said cover away from the surface 6 of inlet connectioni, into a force directed transversely of the longitudinal axis of theinlet connection ll to grippingly engage the outer surface of the inletconnection l.

In the particular embodiment of the invention illustrated in thedrawing, anchor members 6i) comprise legs 60a, 60b, and 69C spacedequidistantly about the periphery of receptacle Preferably there shouldbe at least three such spaced legs welded or otherwise rigidly attachedto cover to provide uniform sealing about the passage 2. However, suchseal could be provided by two or more such legs spaced thereabout.

Each leg 69a, 60h and 6th: is secured to the skirt 8a of cover S andextends downwardly therefrom. The lower end of each of said legs isturned inwardly at its lower end to provide a hooklike member 6d.

As best illustrated in FIGS. II and III of the drawing, hook portions 64on the lower ends of legs 60a, Gibb, and 60C have shaped, tapered,downwardly converging surfaces 66 formed thereon.

Slipring assembly 62 is preferably formed in segments 62a, 62h, and 62C,the number of segments preferably corresponding to the number of legs60a, 60h, and 60C.

Each of the segments 62a, 62h, and 62C has outwardly extending lugs 68aand 68 b welded or otherwise rigidly secured to opposite ends thereof,each of said lugs having an aperture 69 extending therethrough. Theslipring segments are secured together by the connectors such as bolts70 which extend through apertures 69 in lugs 68a and 68h on therespective segments.

As best illustrated in FIGS. III AND IV of the drawings, spaces 7ll areprovided between the ends of the respective segments 62a, 62h and 62Csuch that tightening of nuts 72 on threaded bolts 7i) urges the segmentsinto gripping engagernent with the outer surface of inlet connection l.It should be noted that connectors 70 do not restrict movement of ringsegments 62a, 62h and 62C inwardly.

Each of the segments 62a, 62h, and 62e has an inclined surface 76 on theback side thereof which is disposed in sliding relation with inclinedsurface 66 on the lower ends of legs 60a, 6ilb and 60C. Referring toFIG. II of the drawing, it should be readily apparent that theinclination of surfaces 66 and 76 cause abrasive surfaces 75 on cach ofthe segments 62a, 62b, and 62C to be urged into gripping relation withinlet connection i when a force is applied to cover 8, tending toseparate said cover from inlet connection ll.

In the embodiment of the invention illustrated in FIG. Il of thedrawing, the abrasive surface '75 is rough, having teeth 75a formedtherein.

In the embodiment of the invention illustrated in FIG. V of the drawing,the abrasive surface 75 of slip ring segments 62a, 62h, and 62C has anabrasive lining 75h bonded or otherwise secured thereto which is urgedinto frictional engagement with inlet connection I.

when pressure inside cover exerts a force tending to separate said coverfrom inlet connection ll a force equal and opposite to that exerted bylegs Mia, 60h and 60C upon slip ring segments 62a, 62h, and 62C isexerted outwardly on legs 60a, 60h, and 6de, tending to bend themoutwardly. Therefore, to prevent bending of the legs 66a, ib, and 60Coutwardly, suitable means such as ring S0, is provided thereabout toprevent deformation of said legs. Ring 80 is welded or otherwise rigidlysecured to the lower ends of legs 60a, 60h, and 60C.

From the foregoing it should be readily apparent that inclined surface66 on legs 60a, obb, and 66C form a cup or socket having across-sectional area which decreases downwardly for receiving asubstantially conical shaped slipring assembly 62.

High fluid pressure in passage 2 of inlet connection l and inside cover8 of the cover assembly causes force of appreciable magnitude to beexerted through slipring assembly 62 against the walls of inletconnection i. In certain installations, it may be necessary to installsuitable support or reinforcing means, such as spreader tube d2 tostiffen or reinforce the walls of tubular member li. While spreader tube82 may be of any desired configuration, the particular apparatusillustrated in FIG. Il of the drawing has a transversely extendingmember 84, having spaced apertures 35 formed therein, to provide addedrigidity to the tubular member 82 Without impeding fluid flow betweenpassage 2 of tubular member l and the inside of cover d.

As best illustrated in FlG. Vl of the drawing, the closure assemblyhereinbefore described may be employed to pressure test a segment ofpipe or other vessel l by securing a closure assembly d over eachopening therein. One end of conduit @il is secured in threaded passage 9of one of the closure assemblies while threaded plug iti is employed toclose the threaded passage in other closure assembly after the pipe ilhas bee purged. The other end of conduit is connected to a suitablesource of pressurized fluid (not shown) for delivering pressurized fluidthrough one of the covers 8 to the inside of pipe ll.

OPERA'I'iON The operation and function of the device hereinbeforedescribed is as follows:

The walls of the vessel are reinforced, if necessary, by positioningspreader S2 in passage 2.

To connect the closure assembly i to the inlet connection ll of atubular member, nuts 72 on bolts 7@ which secure slipring segments 62a,62b, and 62C together are loosened to allow the abrasive surfaces '75 onsaid sliprings to encircle and engage the outer wall of tubular memberll. Nuts '72 are then tightened.

Hand wheel i2 is then rotated to urge seal ring assembly i6 downwardlyinto sealing engagement with surface 6 about passage 2 of tubular memberil. This establishes an initial seal and removes slack between inclinedsurfaces 66 and 76 on legs 60a, 6% and faire and slip ring segments 62a,62b, and 62C, respectively. It will be noted that this operation isquickly, simply, and easily carried out.

The plug i0 is then removed to flush air from the tank after theinjected pressure fluid is connected to the inside of tubular member l.The plug iti is then replaced and the liquid or gas pressure is appliedto the interior of the tank or pressure vessel to test same.

Such injected pressure acts upon the upper surface of seal ring lid toforce flange iii against the upper surface of stiffener ring llZ,sealing therebetween while simultaneously urging stiffener ring i12 andseal means Ztl into sealing engagement with surface 6 about passage 2 intubular member li. The injected pressure also acts upon the innersurface ll'b of lip i7 to urge the outer surface lta of lip il intosealing engagement with the inner surface Zia of recess 2li formed inthe skirt 8a of the cover 3 to press such surface into sealingengagement.

The greater the pressure applied internally of the pressure vessel Ilthe more positive and secure the seal is. It should also be noted thatthe greater the pressure applied internally of the pressure vessel themore positive the gripping action of seal ring segments 62a, 62b, and62e. The seal about passage 2 in tubular member il is uniformly appliedalong both the surface 6 and Zia to provide a uniform seal without areasof leakage.

As hereinbefore pointed out, a source of pressurized fluid may beconnected through a suitable conduit 90, best iliustrated in FlG. Vl, todeliver pressurized fluid to the inside of closure assembly d to sealopposite ends of the tubular member and to deliver pressure to theinside thereof.

It should be readily apparent that other and further embodiments of theinvention may be resorted to without departing from the general conceptof my invention.

Having described my invention l claim:

il. Means for sealing about a passage in a vessel comprising, a sealring receptacle, said receptacle having an annular skirt portion; a sealring assembly slidably disposed in the receptacle, said seal ringassembly having an aperture extending therethrough and having surfacesthereon arranged to be urged into sealing engagement with an innersurface of the skirt portion of the seal ring receptacle and with anouter surface of the vessel; spaced anchor members depending from saidskirt portion; interengaging gripping means connectable between theanchor members and the vessel arranged to grippingly engage the outerwall of the vessel whereby fluid pressure in the vessel urges the sealring assembly into sealing engagement relative to the outer Wall of thevessel about the passage and with the slrirt of the receptacle, andcauses the interengaging means to grip the outer wall ofthe vessel.

2. The combination called for in claim l with the addition of supportmeans insertable into the passage in the vessel, said support meansbeing positioned to prevent deformation of the wall of the vesselgripped by the gripping means.

3. The combination called for in claim l wherein the anchor members havetapered surfaces on the inner ends thereof; and wherein theinterengaging gripping means comprises, slipring segments positionableabout a portion of the vessel, said segments having tapered surfacesthereon slidably engageable with the tapered surfaces on the anchormembers.

4. The combination called for in claim ll with the addition of meansbetween the receptacle and the seal ring assembly to urge the seal ringassembly toward a surface about the passage.

5. The combination called for in claim 43 wherein the means to urge theseal ring sembly toward a surface about the passage comprises a stemmovable through an aperture in the receptacle; and with the addition ofmeans to secure the stem to the seal ring assembly.

6. The combination called for in claim il wherein the seal ring assemblycomprises, an outer lip arranged to be urged by fluid pressure in thereceptacle into sealing engagement with an inner surface of thereceptacle; and an intuzned flange angularly disposed with reference tothe outer lip.

7. The combination called for in claim 3 with the addition of abrasivemeans on the inner side of the slpring segments engageable with an outerwall of the vessel.

3. The combination called for in claim '7 wherein the abrasive meanscomprises teeth formed on at least one of the slipring segments.

9. The combination called for in claim 7 wherein the abrasive meanscomprises abrasive material secured to at least one of the slipringsegments.

it). The combination called for in claim 3 with the addition of meanssecured to the anchor members to prevent deformation of said anchormembers.

llii. An article of manufacture comprising, an annular stiffener ring;an annular shoulder on the outer periphery of the stiffener ring; aresilient piston Carried by the stifener ring, said resilient pistonincluding an outwardly projecting annular lip and an inwardly projectingflange; a backup member carn ried by the piston; and means to secure thebackup member relative to the piston.

R2. The combination called for in claim llll with the addition ofresilient seal means on the stiffener ring in spaced relation from thepiston.

i3. The combination called for in claim l2 wherein the seal means is agasket.

M. The combination called for in claim lill wherein the stiffener ringhas an opening extending through a central portion thereof.

l5. A method of pressure testing a vessel having at least one openingformed therein comprising the steps of, positioning a cover having apiston slidably disposed therein over the opening in the vessel;securing the cover relative to the vessel; and delivering pressurizedfluid through the cover to pressurize the inside of the vessel and toforce the piston into sealing engagement with an outer surface ofthevessel about the opening.

lo. The method called for in claim l5 with the addition of the step ofinserting a support member in the opening prior to positioning the coverover the opening to prevent deformation of walls of the vessel; andwherein the step of securing the cover relative to the vessel comprisesgripping outer surfaces of the vessel at positions substantiallycorresponding to positions which the inner surfaces are engaged by thesupport member.

ll'7. Means for closing an opening in a pressure vessel com prising, asegmented slipring assembly positionable to fric tionally engage aportion of the pressure vessel; seal means positionable adjacent theopening in the pressure vessel, seal means having a passage extendingtherethrough; a recit tacle positionable about the seal ring assembly;and anchor means secured relative to the receptacle and engageable withthe slipring assembly such that internal uid pressure in the pressurevessel urges the seal ring assembly into sealing engagement withsurfaces of the pressure vessel around the opening therein, andsimultaneously urges the receptacle away from the pressure vessel tocause the slipring assembly to frictionally engage a portion of thepressure vessel.

R8. The combination called for in claim ll7 with the addition of meanspositionable relative to the pressure vessel opening to preventdeformation of the pressure vessel opening by forces exerted thereonbythe slipring assembly.

i9. The combination called for in claim i3 wherein the meanspositionable relative to the pressure vessel opening comprises a tubularmember.

2li. Means for sealing about a passage in a vessel comprising, areceptacle having an annular skirt ponion; an annular stiffener ringmade of nonresilient maten'al slidably disposed in the receptacle andhaving an annular recessed area about one end thereof, providing anoutwardly extending shoulder about the other end thereof; a resilientpiston carried by the ring, said resilient piston including an upwardlyprojected annular lip substantially coextensive with the outer surfaceof the shoulder, said ring and piston having apertures extendingtherethrough; spaced anchor members depending .from said skirt portion;interengaging gripping means connectable between the anchor members andthe vessel arranged to grippingly engage the wail of the vessel suchthat fluid pres sure in the vessel urges the ring and piston intosealing engagement relative to the wall of the vessel about the passageand with the skirt of the receptacle, and causes the interengaging meansto grip the wall ofthe vessel.

2li. The combination called for in resilient ring.

22. A method of sealing an opening in a vessel having a passage formedthereinto comprising the steps of, inserting a rigid support memberthrough the passage in the vessel to engage an inner wall of the vessel;positioning seal means about the opening in the vessel; gripping anouter wall of the vessel at a location substantially coinciding with thelocation at which the rigid support member engages the inner wall of thevessel to secure the seai means relative to the vessel; and ap plyingfluid pressure substantially equal to pressure in the ves sel for urgingthe outer surfaces of the vessel adjacent the opening.

23. Apparatus for sealing about a passage comprising, a receptaclehaving an annular skirt portion; a piston slidably disposed in the shirtportion of the receptacle, said piston having an apcr ure extendingtherethrough, said piston further having a deformable lip adapted to beurged into sealing engagement with the skirt portion of the receptacleand a deformable flange movabie into sealing engagement with a surfaceadjacent the passage; spaced anchor members clepending from said skirtportion; means secured to the anchor members to limit lateral movementthereof; and means secured to the anchor members for translating forcetending to move the receptacle away from the passage to force tending tolimit movement of the receptacle relative to surfaces adjacent thepassage.

claim 2li wherein the piston is mounted on the inner end of thestiffener seal means into sealing engagement with

1. Means for sealing about a passage in a vessel comprising, a seal ringreceptacle, said receptacle having an annular skirt portion; a seal ringassembly slidably disposed in the receptacle, said seal ring assemblyhaving an aperture extending therethrough and having surfaces thereonarranged to be urged into sealing engagement with an inner surface ofthe skirt portion of the seal ring receptacle and with an outer surfaceof the vessel; spaced anchor members depending from said skirt portion;interengaging gripping means connectable between the anchor members andthe vessel arranged to grippingly engage the outer wall of the vesselwhereby fluid pressure in the vessel urges the seal ring assembly intosealing engagement relative to the outer wall of the vessel about thepassage and with the skirt of the receptacle, and causes theinterengaging means to grip the outer wall of the vessel.
 2. Thecombination called for in claim 1 with the addition of support meansinsertable into the passage in the vessel, said support means beingpositioned to prevent deformation of the wall of the vessel gripped bythe gripping means.
 3. The combination called for in claim 1 wherein theanchor members have tapered surfaces on the inner ends thereof; andwherein the interengaging gripping means comprises, slipring segmentspositionable about a portion of the vessel, said segments having taperedsurfaces thereon slidably engageable with the tapered surfaces on theanchor members.
 4. The combination called for in claim 1 with theaddition of means between the receptacle and the seal ring assembly tourge the seal ring assembly toward a surface about the passage.
 5. Thecombination called for in claim 4 wherein the means to urge the sealring assembly toward a surface about the passage comprises a stemmovable through an aperture in the receptacle; and with the addition ofmeans to secure the stem to the seal ring assembly.
 6. The combinationcalled for in claim 1 wherein the seal ring assembly comprises, an outerlip arranged to be urged by fluid pressure in the receptacle intosealing engagement with an inner surface of the receptacle; and aninturned flange angularly disposed with reference to the outer lip. 7.The combination called for in claim 3 with the addition of abrasivemeans on the inner side of the slipring segments engageable with anouter wall of the vessel.
 8. The combination called for in claim 7wherein the abrasive means comprises teeth formed on at least one of theslipring segments.
 9. The combination called for in claim 7 wherein theabrasive means comprises abrasive material secured to at least one ofthe slipring segments.
 10. The combination called for in claim 3 withthe addition of means secured to the anchor members to preventdeformation of saId anchor members.
 11. An article of manufacturecomprising, an annular stiffener ring; an annular shoulder on the outerperiphery of the stiffener ring; a resilient piston carried by thestiffener ring, said resilient piston including an outwardly projectingannular lip and an inwardly projecting flange; a backup member carriedby the piston; and means to secure the backup member relative to thepiston.
 12. The combination called for in claim 11 with the addition ofresilient seal means on the stiffener ring in spaced relation from thepiston.
 13. The combination called for in claim 12 wherein the sealmeans is a gasket.
 14. The combination called for in claim 11 whereinthe stiffener ring has an opening extending through a central portionthereof.
 15. A method of pressure testing a vessel having at least oneopening formed therein comprising the steps of, positioning a coverhaving a piston slidably disposed therein over the opening in thevessel; securing the cover relative to the vessel; and deliveringpressurized fluid through the cover to pressurize the inside of thevessel and to force the piston into sealing engagement with an outersurface of the vessel about the opening.
 16. The method called for inclaim 15 with the addition of the step of inserting a support member inthe opening prior to positioning the cover over the opening to preventdeformation of walls of the vessel; and wherein the step of securing thecover relative to the vessel comprises gripping outer surfaces of thevessel at positions substantially corresponding to positions which theinner surfaces are engaged by the support member.
 17. Means for closingan opening in a pressure vessel comprising, a segmented slipringassembly positionable to frictionally engage a portion of the pressurevessel; seal means positionable adjacent the opening in the pressurevessel, said seal means having a passage extending therethrough; areceptacle positionable about the seal ring assembly; and anchor meanssecured relative to the receptacle and engageable with the slipringassembly such that internal fluid pressure in the pressure vessel urgesthe seal ring assembly into sealing engagement with surfaces of thepressure vessel around the opening therein, and simultaneously urges thereceptacle away from the pressure vessel to cause the slipring assemblyto frictionally engage a portion of the pressure vessel.
 18. Thecombination called for in claim 17 with the addition of meanspositionable relative to the pressure vessel opening to preventdeformation of the pressure vessel opening by forces exerted thereon bythe slipring assembly.
 19. The combination called for in claim 18wherein the means positionable relative to the pressure vessel openingcomprises a tubular member.
 20. Means for sealing about a passage in avessel comprising, a receptacle having an annular skirt portion; anannular stiffener ring made of nonresilient material slidably disposedin the receptacle and having an annular recessed area about one endthereof, providing an outwardly extending shoulder about the other endthereof; a resilient piston carried by the ring, said resilient pistonincluding an upwardly projected annular lip substantially coextensivewith the outer surface of the shoulder, said ring and piston havingapertures extending therethrough; spaced anchor members depending fromsaid skirt portion; interengaging gripping means connectable between theanchor members and the vessel arranged to grippingly engage the wall ofthe vessel such that fluid pressure in the vessel urges the ring andpiston into sealing engagement relative to the wall of the vessel aboutthe passage and with the skirt of the receptacle, and causes theinterengaging means to grip the wall of the vessel.
 21. The combinationcalled for in claim 20 wherein the resilient piston is mounted on theinner end of the stiffener ring.
 22. A method of sealing an opening in avessel having a passage formed thereinto comprising the sTeps of,inserting a rigid support member through the passage in the vessel toengage an inner wall of the vessel; positioning seal means about theopening in the vessel; gripping an outer wall of the vessel at alocation substantially coinciding with the location at which the rigidsupport member engages the inner wall of the vessel to secure the sealmeans relative to the vessel; and applying fluid pressure substantiallyequal to pressure in the vessel for urging the seal means into sealingengagement with outer surfaces of the vessel adjacent the opening. 23.Apparatus for sealing about a passage comprising, a receptacle having anannular skirt portion; a piston slidably disposed in the skirt portionof the receptacle, said piston having an aperture extendingtherethrough, said piston further having a deformable lip adapted to beurged into sealing engagement with the skirt portion of the receptacleand a deformable flange movable into sealing engagement with a surfaceadjacent the passage; spaced anchor members depending from said skirtportion; means secured to the anchor members to limit lateral movementthereof; and means secured to the anchor members for translating forcetending to move the receptacle away from the passage to force tending tolimit movement of the receptacle relative to surfaces adjacent thepassage.